There is a series of widely differing possibilities for fastening turbochargers to a base. Since the turbochargers used at the present time mostly have uncooled casings, with turbochargers being fastened to a mostly relatively cool base, there is the problem of different thermal expansions between turbocharger and base which lead to stresses in the fastening device. In order to solve this problem, as a rule, separate fastening feet are introduced between turbocharger and base which, by virtue of a special configuration, can absorb the different expansions. Moreover, these fastening feet also often allow a spatially variable orientation of at least parts of the casing of the turbocharger. Separate fastening feet of the type mentioned are known, for example, from DE-A-4432073 and DE-A13641478.
Turbochargers for special applications usually have only one specific position for the gas outlet casing, for example vertically upward in locomotives. In such cases, a fastening foot connected in one piece to the gas outlet casing is much more cost-effective in terms of production and assembly than a separate fastening foot. As regards cooled gas outlet casings, in which virtually no thermal expansion differences occur between base and casing, the integrally formed fastening foot does not present any problems. One example of such a fastening foot integrally formed on a cooled gas outlet casing may be gathered from the article “New turbochargers for medium and larger engines”, Diesel and Gas Turbine Progress, pages 36f, December 1968. Since the production and operation of turbochargers with a cooled gas outlet casing are more complicated and more costly, as compared with turbochargers with an uncooled gas outlet casing, there is a search for a possibility of utilizing both the advantages of turbochargers with an integrally formed fastening foot and the advantages of turbochargers with an uncooled gas outlet casing.